Short-circuiting member, commutator, and method of manufacturing short-circuiting member

ABSTRACT

A short-circuiting member for preventing a commutator from being elongated in the axial direction without increasing the types of different components. The short-circuiting member includes components, each having outer and inner circumferences. Each component includes outer circumference terminals arranged along the outer circumference, inner circumference terminals arranged along the inner circumference, and connection portions connecting a corresponding one of the outer circumference terminals and a corresponding one of the inner circumference terminals that are separated from each other by a predetermined angle in a circumferential direction. The outer and inner circumference terminals are substantially formed along the same plane. The components are laminated in a state in which the connection portions of one of the components are reversed to the connection portions of another one of the components. The outer circumference terminals that are adjacent in a lamination direction are in contact with each other, the inner circumference terminals that are adjacent in the lamination direction are in contact with each other, and the connection portions that are adjacent in the lamination direction are not in contact with each other.

FIELD OF THE INVENTION

The present invention relates to a commutator for a motor, and moreparticularly, to a short-circuiting member for short-circuitingpredetermined segments of a commutator and a method for manufacturing ashort-circuiting member.

BACKGROUND OF THE INVENTION

In conventional motors having power-feeding brushes, among a pluralityof segments arranged in a commutator, predetermined segments may beshort-circuited. When predetermined segments are short-circuited in sucha motor, current flows through segments that are not in contact withpower-feeding brushes. This reduces the quantity of power-feedingbrushes that are required in a motor.

For example, with the structure described above in which predeterminedsegments are short-circuited, the predetermined segments areshort-circuited by using a short-circuit wire or by bypassing a windingwire that is wound around a core.

A motor including an equalizer (short-circuiting member) and acommutator (main body) fixed to the equalizer in the axial direction ofa rotor is known in the prior art (refer to, for example, PatentPublication No. 1). The commutator includes a plurality of segments, andthe equalizer includes a large number of terminals and insulating platesthat are alternately laminated in the axial direction forshort-circuiting predetermined segments.

A commutator including different kinds of terminals that are embedded ininsulators for short-circuiting predetermined segments (where eachterminal is arranged at a different position in the axial direction) isalso known (refer to, for example, Patent Publication 2).

However, when predetermined segments are short-circuited by using thewire such as the short-circuit wire as described above, space foraccommodating the wire needs to be provided between the commutator(segments) and the armature core. The commutator (and the armature)including the wire accommodating space is elongated in the axialdirection. Further, when predetermined segments are short-circuited bythe equalizer (short-circuiting member), which includes many terminalsand insulating plates that are alternately laminated, the equalizer isconnected to the commutator (main body) in the axial direction. Thiselongates the commutator (and the armature), which includes theequalizer, in the axial direction. As a result, the motor is enlarged.

In a commutator including different types of terminals that are embeddedin insulators for short-circuiting predetermined segments, the terminalsare accommodated in the commutator (insulators). This prevents thecommutator from being elongated in the axial direction. However, withthis structure, the terminals are arranged at different positions in theaxial direction. Thus, different types of terminals become necessary.Accordingly, there is a need for dies corresponding to the differentkinds of terminals, and different kinds of components must be handledthereby causing the assembly operation to be complicated. This increasesthe manufacturing cost of the commutator or the motor including thecommutator.

The present invention provides a short-circuiting member, a commutator,and a method for manufacturing a short-circuiting member that prevent acommutator from being elongated in the axial direction and do notincrease the number of types of components.

-   Patent Publication 1-   Japanese Laid-Open Patent Publication No. 2000-60073-   Patent Publication 2-   Japanese Laid-Open Patent Publication No. 2003-189547

SUMMARY OF THE INVENTION

A first aspect of the present invention provides a short-circuitingmember. The short-circuiting member includes a plurality of components,each having an outer circumference and an inner circumference. Each ofthe plurality of components includes a plurality of outer circumferenceterminals arranged along the outer circumference. A plurality of innercircumference terminals are arranged along the inner circumference. Eachof a plurality of connection portions connects a corresponding one ofthe outer circumference terminals and a corresponding one of the innercircumference terminals with the connection portions separated from eachother by a predetermined angle in a circumferential direction. Theplurality of outer circumference terminals, the plurality of innercircumference terminals, and the plurality of connection portions aresubstantially formed along the same plane. The plurality of componentsare laminated in a state in which the connection portions of one of theplurality of components are reversed to the connection portions ofanother one of the plurality of components. The outer circumferenceterminals that are adjacent in a lamination direction are in contactwith each other, the inner circumference terminals that are adjacent inthe lamination direction are in contact with each other, and theconnection portions that are adjacent in the lamination direction arenot in contact with each other.

A second aspect of the present invention provides a commutator. Thecommutator includes a short-circuiting member and a plurality ofsegments connected to a plurality of outer circumference terminals or aplurality of inner circumference terminals.

A third aspect of the present invention provides a commutator. Thecommutator includes a commutator main body having a plurality ofsegments arranged along a circumference and a short-circuiting memberincluding a plurality of components, each having an outer circumferenceand an inner circumference. Each of the plurality of components includesa plurality of outer circumference terminals arranged along the outercircumference, a plurality of inner circumference terminals arrangedalong the inner circumference, and a plurality of connection portions.Each connection portion connects a corresponding one of the outercircumference terminals and a corresponding one of the innercircumference terminals with the connection portions separated from eachother by a predetermined angle in a circumferential direction. Theplurality of outer circumference terminals, the plurality of innercircumference terminals, and the plurality of connection portions aresubstantially formed along the same plane. The plurality of componentsare laminated in a state in which the connection portions of one of theplurality of components are reversed to the connection portions ofanother one of the plurality of components. The outer circumferenceterminals that are adjacent in a lamination direction are in contactwith each other. The inner circumference terminals that are adjacent inthe lamination direction are in contact with each other. The connectionportions that are adjacent in the lamination direction are not incontact with each other.

A fourth aspect of the present invention is a method for manufacturing ashort-circuiting member. The method includes the steps of performing apunching process on a plurality of conductive plate members so that theplurality of connection portions are spaced from one another in acircumferential direction and shaping-stage connection portions areformed for connecting either one of the plurality of outer circumferenceterminals and the inner circumference terminals, laminating theplurality of punched-out conductive plate members so that the connectionportions of one of the plurality of components are reversed to theconnection portions of another one of the plurality of components, andremoving the shaping-stage connection portions from the plurality oflaminated conductive plate members.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a motor having a commutator accordingto a preferred embodiment of the present invention;

FIG. 2 is a cross-sectional view of the motor of FIG. 1;

FIG. 3 is a cross-sectional view of the commutator of FIG. 1;

FIG. 4A is a plan view of a short-circuiting member included in thecommutator of FIG. 1;

FIG. 4B is a cross-sectional view taken along line 4B-4B in FIG. 4A;

FIG. 5 is an explanatory diagram for describing a manufacturing methodfor the short-circuiting member of FIG. 4A;

FIG. 6 is a diagram for describing the manufacturing method for theshort-circuiting member of FIG. 4A;

FIG. 7 is a diagram for describing the manufacturing method for theshort-circuiting member of FIG. 4A;

FIG. 8 is a diagram for describing the manufacturing method for theshort-circuiting member of FIG. 4A;

FIG. 9 is an explanatory diagram for describing the manufacturing methodfor the short-circuiting member of FIG. 4A;

FIG. 10 is an explanatory diagram for describing a structure for fixinga commutator main body and the short-circuiting member of the commutatorof FIG. 1;

FIG. 11 is an explanatory diagram for describing the structure forfixing the commutator main body and the short-circuiting member of thecommutator of FIG. 1;

FIG. 12 is an explanatory diagram for describing an armature of themotor of FIG. 1 that is developed on a plane;

FIG. 13 is a perspective view showing a commutator according to a firstmodification of the present invention;

FIG. 14 is a perspective view showing a commutator according to a secondmodification of the present invention;

FIG. 15 is a perspective view showing a commutator according to a thirdmodification of the present invention;

FIG. 16 is a perspective view showing a commutator according to a fourthmodification of the present invention;

FIG. 17 is a perspective view showing a commutator according to a fifthmodification of the present invention;

FIG. 18 is an explanatory diagram for describing a short-circuitingmember according to a sixth modification of the present invention;

FIG. 19 is an explanatory diagram for describing a manufacturing methodfor the short-circuiting member of FIG. 18;

FIG. 20 is an explanatory diagram for describing a short-circuitingmember according to a seventh modification of the present invention;

FIG. 21 is a schematic cross-sectional diagram showing a cross-sectionof the short-circuiting member of FIG. 20; and

FIG. 22 is a schematic cross-sectional diagram showing a cross-sectionof a short-circuiting member according to an eighth modification of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A motor 101 including a commutator S that includes 24 segments accordingto a preferred embodiment of the present invention will now be describedwith reference to FIGS. 1 to 12.

As shown in FIGS. 1 and 2, the motor 101 of the preferred embodimentincludes a stator 102 and an armature (rotor) 103. The stator 102includes a yoke housing 104, which has a substantially tubular shapewith a closed bottom, and a plurality of (six in the preferredembodiment) permanent magnets 105, which are arranged on the innercircumferential surface of the yoke housing 104 at equiangularintervals. An end frame 106 is fixed to the yoke housing 104 to closethe opening of the yoke housing 104. The end frame 106 holds an anodepower feeding brush B1 and a cathode power feeding brush B2, which areconnected to an external power supply.

The armature 103 includes a rotary shaft 107, which is made of metal, anarmature core K, which is fixed to the rotary shaft 107, and acommutator S, which is fixed to the rotary shaft 107. A bearing 108 a isheld on a middle portion of the bottom of the yoke housing 104, and abearing 108 b is held on a middle portion of the end frame 106. Thebearing 108 a holds one end of the rotary shaft 108 in a rotatablemanner. The bearing 108 b holds a middle portion of the rotary shaft 107in a rotatable manner. In this state, the armature core K faces thepermanent magnets 105 and is surrounded by the permanent magnets 105.

The armature core K has eight teeth T1 to T8, which extend radially fromthe rotary shaft 107. Slots S1 to S8 are formed between the teeth T1 toT8. Winding wires M1 to M8 are respectively wound around the teeth T1 toT8 in a manner that the winding wires M1 to M8 extend through the slotsS1 to S8. The two ends of the winding wires M1 to M8 are connected tothe commutator S. FIG. 12 is a schematic diagram showing the armature103 unfolded along a plane.

The commutator S includes a commutator main body Sa and ashort-circuiting member Sb, as shown in FIG. 3. The commutator main bodySa includes a main body insulator H, which has a substantiallycylindrical shape, and a plurality of (24 in the preferred embodiment)segments 1 to 24 (refer to FIG. 12 as FIG. 3 only shows two segments),which are arranged on the outer circumferential surface of the main bodyinsulator H in the circumferential direction. The segments 1 to 24 forma substantially cylindrical shape as a whole. The anode and cathodepower feeding blushes B1 and B2 come in contact with (press against) theouter circumferential surface of the segments 1 to 24. A recess 25(refer to FIGS. 9 to 11) is formed in the end of each of the segments 1to 24 of the preferred embodiment. A short-circuiting memberaccommodating recess 26 that has the same depth as the recesses 25 isformed in the end of the main body insulator H. The short-circuitingmember accommodating recess 26 is annular and extends from the outercircumference of the main body insulator H to the vicinity of the innercircumference of the main body insulator H. A positioning recess 27,used for positioning, is formed at a predetermined position in thecircumferential direction of the short-circuiting member accommodatingrecess 26. The inner circumference of the main body insulator H definesa shaft hole 28, through which the rotary shaft 107 is inserted. Theshort-circuiting member accommodating recess 26 is formed in the mainbody insulator H in the vicinity of the inner circumference (the shafthole 28) of the main body insulator H. Thus, an annular portion 29 isformed between the inner circumference of the short-circuiting memberaccommodating recess 26 and the inner circumference of the main bodyinsulator H.

As shown in FIGS. 4A and 4B, the short-circuiting member Sb includesfirst and second components 31 a and 31 b, which are used to produce ashort-circuit and which have the same structure, and an insulator 32.Each of the first and second components 31 a and 31 b is a circularplate having a central opening. The first and second components 31 a and31 b include a plurality of outer circumference terminals 33 a and 33 b,which are arranged along the outer circumference, a plurality of innercircumference terminals 34 a and 34 b, which correspond to the outercircumference terminals 33 a and 33 b and which are arranged along theinner circumference, and a plurality of connection portions 35 a and 35b, which connect the corresponding outer circumference terminals 33 aand 33 b to the corresponding inner circumference terminals 34 a and 34b. In detail, the outer circumference terminals 33 a and 33 b, the innercircumference terminals 34 a and 34 b, and the connection portions 35 aand 35 b are substantially arranged along the same plane. Further, eachof the outer circumference terminals 33 a and 33 b and the correspondingone of the inner circumference terminals 34 a and 34 b are separatedfrom each other by a predetermined angle in the circumferentialdirection and connected to each other by a corresponding one of theconnection portions 35 a and 35 b.

In the preferred embodiment, the outer rim of each of the outercircumference terminals 33 a and 33 b has a predetermined width. Morespecifically, hooking portions 36 a and 36 b for hooking the windingwires M1 to M8 are formed on the rims of the outer circumferenceterminals 33 a and 33 b. The hooking portions 36 a and 36 b extendradially outward from the middle of the rims. The hooking portions 36 aand 36 b function as insertion projections that can be inserted in therecesses 25 in the axial direction. In the preferred embodiment, thefirst and second components 31 a and 31 b include twenty-four outercircumference terminals 33 a and 33 b, twenty-four inner circumferenceterminals 34 a and 34 b, twenty-four connection portions 35 a and 35 b,and twenty-four hooking portions 36 a and 36 b. The above predeterminedangle is 60 degrees in the preferred embodiment. More specifically, eachof the connection portions 35 a and 35 b connects the corresponding oneof the outer circumference terminals 33 a and 33 b and the correspondingone of the inner circumference terminals 34 a and 34 b in a manner thatthe outer circumference terminal and the inner circumference terminalare separated from each other by 60 degrees (by a distance correspondingto four terminals in the preferred embodiment) in the circumferentialdirection. The above expression of “being substantially in the sameplane” is intended to mean that each portion is formed in the same layerand are not located at different levels in the axial direction althoughrecesses and projections (stepped portions) may be included. Theconnection portions 35 a and 35 b of the preferred embodiment arethinner than the outer circumference terminals 33 a and 33 b, the innercircumference terminals 34 a and 34 b, and the hooking portions 36 a and36 b. Thus, stepped portions D (refer to FIG. 4B) are formed on onesurface of each of the components 31 a and 31 b. Further, fittingrecesses (holes) 37 a and 37 b and fitting projections 39 a and 39 b areformed in the outer circumference terminals 33 a and 33 b in a mannerthat the recesses 37 a and 37 b and the projections 39 a and 39 b arealternately adjacent to one another in the circumferential direction(refer to FIG. 5). Fitting recesses (holes) 38 a and 38 b and fittingprojections 40 a and 40 b are formed in the inner circumferenceterminals 34 a and 34 b in a manner that the recesses 38 a and 38 b andthe projections 40 a and 40 b are alternately adjacent to one another inthe circumferential direction (refer to FIG. 5). Each of the fittingrecesses 37 a, 37 b, 38 a, and 38 b, and the fitting projections 39 a,39 b, 40 a, and 40 b is located at a position substantiallycorresponding to the middle of the width of the corresponding one of theouter circumference terminals 33 a and 33 b and the inner circumferenceterminal 34 a and 34 b in the circumferential direction and also locatedat a position substantially corresponding to the middle of the length ofthe corresponding one of the outer circumference terminals 33 a and 33 band the inner circumference terminal 34 a and 34 b in the radialdirection. Further, each of the connection portions 35 a and 35 b isformed along an involute curve. The connection portions 35 a and 35 bare spiral as a whole.

The first and second components 31 a and 31 b are laminated in a mannerthat the connection portions 35 a and the connection portions 35 b arereversed from each other (the spiral direction of the connectionportions 35 a differs from the spiral direction of the connectionportions 35 b). The surfaces of the outer circumference terminals 33 acome in contact with the surfaces of the outer circumference terminals33 b, the surfaces of the inner circumference terminals 34 a come incontact with the surfaces of the inner circumference terminals 34 b, andthe connection portions 35 a do not come in contact with the connectionportions 35 b (due to the stepped portions D). In the first and secondcomponents 31 a and 31 b, the fitting projections 39 a, 39 b, 40 a, and40 b are respectively fitted to the fitting recesses 37 a, 37 b, 38 a,and 38 b so that the outer circumference terminals 33 a and 33 b arefixed to each other and the inner circumference terminals 34 a and 34 bare fixed to each other.

The insulator 32 is formed from an insulating resin material and isarranged between adjacent connection portions 35 a and 35 b. In detail,the insulator 32 is formed to fill gaps between the outer circumferenceterminals 33 a and 33 b, between the inner circumference terminals 34 aand 34 b and between the connection portions 35 a and 35 b. Further, theinsulator 32 includes a positioning projection 32 a, which is formed ata position corresponding to the positioning recess 27 and whichfunctions as a positioning unit for positioning the first and secondcomponents 31 a and 31 b in the circumferential direction.

The short-circuiting member Sb is fixed to the commutator main body Sain a manner that the outer circumference terminals 33 a and 33 b areconnected to the segments 1 to 24. In detail, the short-circuitingmember Sb is arranged in a manner that the positioning projection 32 ais fit in the positioning recess 27 and parts excluding the hookingportions 36 a and 36 b are accommodated within the short-circuitingmember accommodating recess 26. The hooking portions 36 a and 36 b areinserted into and project out of the recesses 25 (from the outercircumference of the commutator main body Sa). As shown in FIGS. 10 and11, the hooking portions 36 a and 36 b are fitted between a pair of arms25 a that form the recess 25 and fixed to each other so that theshort-circuiting member Sb is fixed to the commutator main body Sa.FIGS. 10 and 11 are schematic diagrams partially showing the end of thecommutator S as viewed from the outer side in the radial direction andillustrates a jig J for retaining the hooking portions 36 a and 36 bbetween the arms 25 a. Further, the outer circumference terminals 33 aand 33 b included in the short-circuiting member Sb of the preferredembodiment are designed in a manner that the outer circumference of theshort-circuiting member Sb excluding the hooking portions 36 a and 36 bcomes in contact with the inner circumference of the segments 1 to 24 ina state in which the outer circumference terminals 33 a and 33 b arefixed. Further, the short-circuiting member Sb is arranged in a mannerthat it does not project outward from the end surface of the commutatormain body Sa. The inner circumference terminals 34 a and 34 b includedin the short-circuiting member Sb are located outward from the shafthole 28 in the radial direction. The annular portion 29 of the main bodyinsulator H is arranged between the inner circumference terminals 34 aand 34 b and the shaft hole 28.

Next, the method for manufacturing the short-circuiting member Sb withthe above-described structure will be described in detail.

First, in a punching process, conductive plate members 53 are punchedout in a manner that the connection portions 35 a (35 b) included in onecomponent 31 a (31 b) are spaced from one another in the circumferentialdirection, and an inner side connection portion 51 and an outer sideconnection portion 52, which function as shaping-stage connectionportions, are formed in each conductive plate member 53 as shown in FIG.5. In detail, the inner side connection portion 51 that connects theinner circumference terminals 34 a (34 b) and the outer side connectionportion 52 that connects the outer circumference terminals 33 a (33 b)are formed in each conductive plate member 53. In the preferredembodiment, each conducive plate member 53 is punched out in a mannerthat the outer circumference terminals 33 a (33 b) are spaced from oneanother in the circumferential direction and the inner circumferenceterminals 34 a (34 b) are spaced from one another in the circumferentialdirection. The fitting recesses 37 a, 37 b, 38 a, and 38 b, the fittingprojections 39 a, 39 b, 40 a, and 40 b, and the stepped portions D areformed at the same time. In the preferred embodiment, the punchingprocess is performed by first and second punching operation units 54 and55 in a manner that the connection portions 35 a and 35 b are formed inreversed directions as shown in FIG. 7. FIG. 7 is a schematic diagramshowing a manufacturing apparatus (including the first and secondpunching operation units 54 and 55) and the continuous conductive platemembers 53 as viewed from above, and does not show the punched shapes ofthe conductive plate members 53.

As shown in FIG. 7, the two conductive plate members 53 that are punchedout by the first and second punching operation units 54 and 55 are movedto a lamination operation unit 56 while maintaining the orientations ofthe two conductive plate members 53 to undergo a lamination process. Inthe lamination process, the punched two conductive plate members 53 arelaminated in a manner that the connection portions 35 a and 35 b arereversed from each other as shown in FIG. 6. In this stage, the fittingprojections 39 b are fitted to the fitting recesses 37 a, the fittingprojections 39 a are fitted to the fitting recesses 37 b, the fittingprojections 40 b are fitted to the fitting recesses 38 a, and thefitting projections 40 a are fitted to the fitting recesses 38 b.

Next, in an insulator filling process, an insulating resin material isfilled and cured between the two conductive plate members 53. In detail,the two laminated conductive plate members 53 are placed in a mold thatis not shown, and a molten insulating resin material is filled and curedin gaps formed between the two conductive plate members 53. This formsthe insulator 32. The positioning projection 32 a is formed at the sametime.

Next, in a removing process, the inner side connection portions 51 andthe outer side connection portions 52 of the laminated two conductiveplate members 53 are removed (punched out) as shown by the broken linesin FIG. 8. This completes the manufacture of the short-circuiting memberSb (refer to FIG. 4).

In the short-circuiting member Sb of the above-described structure, theouter circumference terminals 33 a and 33 b (the inner circumferenceterminals 34 a and 34 b) are electrically connected to one another in amanner that they are separated from one another by 120 degrees in thecircumferential direction. Thus, in the commutator S, predeterminedsegments (e.g., set of the segments 1, 9, and 17 and set of the segments5, 13, and 21) are short-circuited by the short-circuiting member Sb (indetail, by the hooking portions 36 a, the outer circumference terminals33 a, the connection portions 35 a, the inner circumference terminals 34a and 34 b, the connection portions 35 b, the outer circumferenceterminals 33 b, and the hooking portions 36 b). Thus, for example, asshown in FIG. 12, current flows not only through the segments 6, 7, 18,and 19 that are in direct contact with the anode and cathode powerfeeding brushes B1 and B2 but also through the segments 2, 3, 10, 11,14, 15, 22, and 23 that are short-circuited with the segments 6, 7, 18,and 19 by the short-circuiting member Sb. This enables many windingwires M1 to M8 to be supplied with current without increasing thequantity of the anode and cathode power feeding brushes B1 and B2.

The preferred embodiment has the advantages described below.

(1) The two components 31 a and 31 b that are formed in the same planeare laminated so that sets of three of the twenty-four outercircumference terminals 33 a and 33 b (the inner circumference terminals34 a and 34 b) spaced at intervals of 120 degrees are electricallyconnected to one another. More specifically, the above structure reduces(as compared with an equalizer according to a prior art technique) thenumber of conductors (including the connection portions 35 a and 35 b)used for short-circuiting purpose in the axial direction (laminationdirection), and thereby prevents the commutator S (armature) from beingelongated in the axial direction. Further, the first and secondcomponents 31 a and 31 b, which are formed in the same plane, are easilyformed from the conductive plate members 53. Since the same components31 a and 31 b are used, the number of different kinds of components doesnot increase. Further, the outer circumference terminals 33 a come indirect contact with the outer circumference terminals 33 b, and theinner circumference terminals 34 a come in direct contact with the innercircumference terminals 34 b. This structure ensures reliable electricalconnection between the terminals without using other members (such aspins) for connecting the terminals. As a result, many different kinds ofdies do not need to be used, and different kinds of components do notneed to be handled. This prevents the manufacturing cost of thecommutator S or a motor including the commutator S from increasing.Further, the short-circuiting member Sb is fixed to the commutator mainbody Sa having the segments 1 to 24 (the short-circuiting member Sb doesnot need to be formed at the same time as when the commutator main bodySa is formed). Thus, the commutator main body Sa can be commonly used ina commutator that does not require the short-circuiting member Sb (doesnot require short-circuiting).

(2) The connection portions 35 a and 35 b are thinner than the outercircumference terminals 33 a and 33 b and the inner circumferenceterminals 34 a and 34 b. The insulator 32 is arranged between theconnection portions 35 a and 35 b that are adjacent in the laminationdirection. Thus, the insulator 32 ensures that the connection portions35 a are prevented from being short-circuited with the connectionportions 35 b. Further, the insulator 32 maintains the distance betweenthe first component 31 a and the second component 31 b.

(3) The main body insulator H includes the positioning recess 27, andthe insulator 32 includes the positioning projection 32 a that is fit inthe recess 27. Thus, the short-circuiting member Sb is easily positionedwith and fixed to the commutator main body Sa. The positioningprojection 32 a is formed in the insulator filling process. Thus, anadditional process for formation of the positioning projection 32 a.

(4) The fitting recesses 37 a, 37 b, 38 a, and 38 b and the fittingprojections 39 a, 39 b, 40 a, and 40 b are alternately formed in thecircumferential direction in the outer circumference terminals 33 a and33 b and the inner circumference terminals 34 a and 34 b. Thus, when thecomponents 31 a and 31 b are laminated, the positions of the fittingrecesses 37 a, 37 b, 38 a, and 38 b respectively coincide with thepositions of the fitting projections 39 a, 39 b, 40 a, and 40 b so thatthe recesses and the projections are easily fitted to each other andfixed to each other.

(5) Each of the connection portions 35 a and 35 b is formed along aninvolute curve. This reduces unnecessary space (unnecessary spaceexcludes space required to ensure insulation between the connectionportions 35 a and 35 b) along a plane (as viewed in the axialdirection). In this case, the area of each part (inner and outer sidesin the radial direction) of the connection portions 35 a and 35 b asviewed in the axial direction is larger as compared with when eachconnection portion is formed with a simple linear shape. As a result,the thickness of the short-circuiting member Sb in the axial directionmay be minimized while insulation between the connection portions 35 aand 35 b is ensured.

(6) The short-circuiting member Sb, excluding the hooking portions 36 aand 36 b, is accommodated in the short-circuiting member accommodatingrecess 26 located inward from the segments 1 to 24 in the radialdirection. This structure prevents brush wear particles from collectingon the short-circuiting member Sb (excluding the hooking portions 36 aand 36 b). In particular, the short-circuiting member Sb does notproject outward (at all) from the end surface of the commutator mainbody Sa in the axial direction in the preferred embodiment. Thisstructure ensures that brush wear particles are prevented fromcollecting on the short-circuiting member Sb (excluding the hookingportions 36 a and 36 b). As a result, the connection portions 35 a and35 b that are adjacent in the circumferential direction in theshort-circuiting member Sb are prevented from being short-circuited.

(7) The short-circuiting member Sb (excluding the hooking portions 36 aand 36 b) is accommodated in the short-circuiting member accommodatingrecess 26 (the short-circuiting member Sb does not project outward fromthe end surface of the commutator main body Sa in the axial direction).Thus, the short-circuiting member Sb does not elongate the commutator Sin the axial direction.

Further, the outer circumference terminals 33 a and 33 b include thehooking portions 36 a and 36 b for holding the winding wires M1 to M8.The hooking portions 36 a and 36 b extend in the radial direction andproject outward from the outer surface of the commutator main body Sa.Thus, the short-circuiting member Sb is overlapped in the axialdirection with the hooking portions of the commutator S (even if theshort-circuiting member Sb is not accommodated within theshort-circuiting member accommodating recess 26). Thus, theshort-circuiting member Sb does not elongate the commutator S in theaxial direction.

(8) The inner circumference terminals 34 a and 34 b of theshort-circuiting member Sb are arranged outward from the shaft hole 28and do not come in contact with the rotary shaft 107. Thus, even whenthe rotary shaft 107 is made of metal, which is a conductive material,like in the preferred embodiment, the short-circuiting member Sb isprevented from being short-circuited with the rotary shaft 107(insulation is ensured). In addition, the annular portion 29 of the mainbody insulator H is arranged between the inner circumference terminals34 a and 34 b and the shaft hole 28. The annular portion 29 ensuresprevention of short-circuiting between the short-circuiting member Sband the rotary shaft 107. Further, the inner circumference terminals 34a and 34 b are engaged with the annular portion 29. As a result, theshort-circuiting member Sb is firmly fixed to the main body insulator H.

(9) The recesses 25 are formed in the ends of the segments 1 to 24. Thehooking portions 36 a and 36 b, which extend outward in the radialdirection and are inserted in the recesses 25 in the axial direction,are formed in the outer circumference terminals 33 a and 33 b. Thehooking portions 36 a and 36 b are inserted in the recesses 25 so thatthe short-circuiting member Sb is arranged at the end of the commutatormain body Sa. As a result, the short-circuiting member Sb is easilyarranged at the end of the commutator main body Sa and fixed in thecircumferential direction by moving the short-circuiting member Sb inthe axial direction with respect to the commutator main body Sa andinserting the hooking portions 36 a and 36 b of the short-circuitingmember Sb into the recesses 25. Further, the short-circuiting member Sbis easily positioned in the axial direction and the short-circuitingmember Sb is prevented from vibrating in the axial direction by placingthe hooking portions 36 a and 36 b in contact with the bottoms of therecesses 25.

(10) The recesses 25 are formed in the ends of the segments 1 to 24, andthe hooking portions 36 a and 36 b fitted and fixed to the two arms 25 athat form the recess 25. Thus, the hooking portions 36 a and 36 b areeasily fixed to the commutator main body Sa and the short-circuitingmember Sb is easily fixed to the commutator main body Sa. This ensuresthat the segments 1 to 24 are electrically connected to the outercircumference terminals 33 a and 33 b by the hooking portions 36 a and36 b.

(11) The outer circumference of the outer circumference terminals 33 aand 33 b excluding the hooking portions 36 a and 36 b comes in contactwith the inner circumference of the segments 1 to 24 in the radialdirection. This structure prevents the short-circuiting member Sb frombeing moved in the radial direction by, for example, a centrifugal forcegenerated when the rotary shaft 107 rotates.

(12) Each of the fitting recesses 37 a, 37 b, 38 a, and 38 b, and thefitting projections 39 a, 39 b, 40 a, and 40 b is formed at a locationthat is substantially the middle of the corresponding one of the outercircumference terminals 33 a and 33 b and the inner circumferenceterminals 34 a and 34 b in the circumferential direction and issubstantially the middle of the corresponding one of the outercircumference terminals 33 a and 33 b and the inner circumferenceterminals 34 a and 34 b in the radial direction. This structurestrengthens the engagement of each part (the outer circumferenceterminals 33 a and 33 b and the inner circumference terminals 34 a and34 b) while maintaining rigidity.

(13) With the above manufacturing method, the inner side connectionportions 51 and the outer side connection portions 52 for connecting theinner and outer sides of the connection portions 35 a and 35 b in theradial direction are formed (the connection portions 35 a and 35 b arenot separated) in the conductive plate members 53 that are punched outin the punching process. Thus, materials (the conductive plate members53) are easily handled in the lamination process (and in the insulatorfilling process). As a result, the short-circuiting member Sb can beeasily manufactured.

(14) With the above manufacturing method, the insulator 32 is formedbetween the connection portions 35 a and 35 b in the insulator fillingprocess before the removing process in which the inner side connectionportions 51 and the outer side connection portions 52 of the laminatedtwo conductive plate members 53 are removed (punching out). Thus, afterthe removing process, the insulator 32 maintains the interval betweenthe first component 31 a and the second component 31 b.

(15) With the above manufacturing method, the punching process isperformed by each of the first and second punching operation units 54and 55 in a manner that the connection portions 35 a and 35 b arereversed from each other. The two conductive plate members 53 that arepunched out by the first and second punching operation units 54 and 55are moved to the common lamination operation unit 56 while maintainingtheir orientations, and then the lamination process is performed. Thisenables the operation units 54 to 56 to be constantly operated. Further,this eliminates the need for the operation of turning around one of thetwo conductive plate members 53 to reverse the connection portions 35 aand 35 b with respect to each other. As a result, the short-circuitingmember Sb is efficiently manufactured at a high speed.

The above embodiment may be modified in the following forms.

The commutator S (the commutator main body Sa and the short-circuitingmember Sb) in the above embodiment may be modified to a commutator 61 (acommutator main body 62 and a short-circuiting member 63) as shown inFIG. 13. As shown in FIG. 13, the short-circuiting member 63 includesouter circumference terminals 63 a shaped differently from the outercircumference terminals (33 a and 33 b) of the above embodiment. Indetail, the hooking portions (36 a and 36 b) for hooking the windingwires in the above embodiment are not formed in the outer circumferenceterminals 63 a. Further, the width of each outer circumference terminal63 a (width in the circumferential direction as viewed in the axialdirection) is set to have substantially the same width as eachconnection portion 63 b (having substantially the same shape as theconnection portions 35 a and 35 b of the above embodiment). Each segment64 of the commutator main body 62 has a pair of hooking portions 64 a(for hooking a winding wire) that project outward in the radialdirection. The outer circumference terminals 63 a are arranged (fixed byswaging) in a manner that each outer circumference terminal 63 a issandwiched between the base ends of one pair of hooking portions 64 a.In this modification, the parts sandwiching each outer circumferenceterminal 63 a form the recess of each segment 64, and the sandwichedpart of each outer circumference terminal 63 a forms the insertionprojection. Further, the short-circuiting member 63 partially projectsfrom the commutator main body 62 in the axial direction (extends outsidethe commutator main body 62). In this modification, each outercircumference terminal 63 a does not include a hooking portion and has auniform width. Thus, the outer circumference terminals 63 a do not comein contact with the inner circumference of the segments 64.

The commutator S (the commutator main body Sa and the short-circuitingmember Sb) of the above embodiment may be modified to a commutator 66 (acommutator main body 67 and a short-circuiting member 68) shown in FIG.14. As shown in FIG. 14, the short-circuiting member 68 is formed tohave substantially the same shape as the short-circuiting member of theabove modification (refer to FIG. 13). However, outer circumferenceterminals 68 a do not project outward from the outer circumferentialsurface of the commutator main body 67 (segments 69) in the radialdirection. In detail, the outer ends of the outer circumferenceterminals 68 a substantially coincide with the outer circumferentialsurface of the commutator main body 67. A pair of hooking portions 69 a(for hooking a winding wire) that project outward in the radialdirection is formed at a first end of each segment 69 in the axialdirection. A pair of holding portions 69 b that project in the axialdirection is formed at a second end of each segment 69 in the axialdirection. The outer circumference terminals 68 a are arranged (fixed byswaging) in a manner that each outer circumference terminal 68 a issandwiched by one pair of holding portions 69 b formed at the second endof each segment 69 in the axial direction. In this modification, theportions sandwiching each outer circumference terminal 68 a (holdingportions 69 b) form the recess of each segment 69, and the sandwichedportion of each outer circumference terminal 68 a forms an insertionprojection. Each outer circumference terminal 68 a does not have ahooking portion and has a uniform width. Thus, the outer circumferenceterminals 68 a do not come in contact with the inner circumference ofthe segments 69.

The commutator S (the commutator main body Sa and the short-circuitingmember Sb) of the above embodiment may be modified to a commutator 71 (acommutator main body 72 and a short-circuiting member 73) shown in FIG.15. As shown in FIG. 15, the short-circuiting member 73 is formed tohave substantially the same shape as the short-circuiting member of theabove modification (refer to FIG. 14). However, outer circumferenceterminals 73 a do not project outward from the outer circumferentialsurface of the commutator main body 72 (segments 74) in the radialdirection. In detail, the outer ends of the outer circumferenceterminals 73 a are located inward from the outer circumferential surfaceof the commutator main body 72. A connecting terminal 74 a that projectsin the axial direction is formed at a first end of each predeterminedsegment 74. A connecting recess 74 b is formed at a second end of eachof the segments 74. The outer circumference terminals 73 a are arranged(welded) in a manner that each outer circumference terminal 73 a isaccommodated in the connecting recess 74 b formed at the second end ofeach segment 74. In this modification, the part accommodated in theconnecting recess 74 b of the outer circumference terminal 73 a formsthe insertion projection. Further, the outer circumference terminals 73a come in contact with the inner circumference of the segments 74. Theconnecting terminals 74 a are inserted in coil terminals arranged in anarmature core that is not shown so that winding wires are connected tothe commutator 71.

The commutator S (the commutator main body Sa and the short-circuitingmember Sb) of the above embodiment may be modified to a commutator 76(commutator main body 77 and short-circuiting member 78) shown in FIG.16. As shown in FIG. 16, the short-circuiting member 78 is formed tohave substantially the same shape as the short-circuiting member of theabove modification (refer to FIG. 15). However, outer circumferenceterminals 78 a and 78 b of each pair in different layers are formed atdifferent positions in the circumferential direction (do not come incontact with each other in the lamination direction (axial direction)).Each of the outer circumference terminals 78 a and 78 b has a bentportion 78 c that is bent in the axial direction. The bent portions 78 cof each pair of the outer circumference terminals 78 a and 78 b come incontact with each other in the circumferential direction. A connectingterminal 79 a that projects in the axial direction is formed at a firstend of each predetermined segment 79. A projection wall 79 b thatprojects in the axial direction is formed at a second end of each of thesegments 79. The outer circumference terminals 78 a and 78 b arearranged (fixed by welding) in a manner that the bent portion 78 c ofeach outer circumference terminal comes in contact with the innercircumference of the projection wall 79 b in the radial direction at thesecond end of each segment 79 in the axial direction. In this example,the connecting terminals 79 a are inserted in coil terminals arranged inan armature core that is not shown so that the commutator 76 isconnected to winding wires.

The commutator S (the commutator main body Sa and the short-circuitingmember Sb) of the above embodiment may be modified to a commutator 81 (acommutator main body 82 and a short-circuiting member 83) shown in FIG.17. As shown in FIG. 17, the short-circuiting member 83 includes outercircumference terminals 83 a shaped differently from the outercircumference terminals 33 a and 33 b of the above embodiment. Indetail, each outer circumference terminal 83 a includes an auxiliaryhooking portion 83 b for hooking a winding wire. More specifically, aconnecting terminal 84 a that projects in the axial direction is formedat one end of each predetermined segment 84 in the axial direction. Theauxiliary hooking portions 83 b are formed and arranged (fixed bywelding) to avoid the connecting terminals 84 a (arranged at positionsdifferent from one another in the circumferential direction and come incontact with the connecting terminals 84 a in the circumferentialdirection in this modification). In this modification, the connectingterminals 84 a are inserted in coil terminals arranged in an armaturecore that is not shown or winding wires are hooked on the auxiliaryhooking portions 83 b so that the winding wires are connected to thecommutator 81. In other words, the winding wires may be connected to thecommutator 81 by at least either one of the connecting terminals 84 aand the auxiliary hooking portions 83 b.

In the above embodiment, the insulator 32 is arranged between theconnection portions 35 a and 35 b that are adjacent in the laminationdirection. Alternatively, the insulator may be eliminated and a gap maybe formed between the connection portions that are adjacent in thelamination direction. In this case, the gap prevents the adjacentconnection portions in the lamination direction from beingshort-circuited. Further, in the above embodiment, the insulator 32 isarranged between the connection portions 35 a and 35 b that are adjacentin the circumferential direction. Alternatively, the insulator may beeliminated so and a gap may be formed between the connection portionsthat are adjacent in the circumferential direction. In this case, thegap prevents the adjacent connection portions in the circumferentialdirection from being short-circuited.

In addition to the insulator 32, the short-circuiting member Sb of theabove embodiment may further include an interval maintaining member formaintaining the interval between the adjacent connection portions 35 aand 35 b in the lamination direction.

For example, as shown in FIGS. 18 and 19, interval maintaining members87 and 88 for maintaining the interval between the adjacent connectionportions 35 a and 35 b in the lamination direction (axial direction) arearranged in a mold 86 (refer to FIG. 19) in the insulator fillingprocess (before a resin material is filled). In this state, theinsulator (molten insulating resin material) 32 is filled. The intervalmaintaining members 87 and 88 are arranged to come in contact with thefacing surfaces of the connection portions 35 a and 35 b and come incontact with the mold 86 through a gap in the circumferential directionthat is formed between the facing connection portions 35 a and 35 b.This prevents the connection portions 35 a and 35 b from being bent inthe lamination direction (axial direction) by the pressure of theinsulator 32 (molten insulating resin material) that is filled so thatthe connection portions 35 a and 35 b are prevented from beingshort-circuited. FIGS. 18 and 19 show one example of a short-circuitingmember Sc in which the hooking portions 36 a and 36 b are not formed.FIG. 18 shows the short-circuiting member Sc in a state before theinsulator 32 is formed. FIG. 19 schematically shows a cross-section ofthe connection portions 35 a and 35 b to facilitate description of themanufacturing method. In this example, the inner side connection portion51 and the outer side connection portion 52 are not formed in eachconductive plate member in the punching process. However, in thepunching process according to this modification, the conductive platemembers are punched out in a manner that outer circumference terminalconnection portions 91 (indicated by broken lines in FIG. 18),functioning as shaping-stage connection portions for connecting theouter sides of the connection portions 35 a and 35 b in the radialdirection, are formed. Thus, inner circumference terminals 89 are spacedfrom one another in the circumferential direction, and outercircumference terminals 90 are not spaced from one another in thecircumferential direction. In this modification, in a state in which theouter circumference terminal connecting portions 91 have been formed andthe segments of the commutator main body are not spaced from one anotherin the circumferential direction, a cylindrical conductive plate member(a conductive plate member for forming segments) is arranged on theouter circumference of the segments. Afterwards, the outer circumferenceterminals 90 and the outer circumference terminal connection portions 91are fixed to the cylindrical conductive plate member through welding orthe like so that the short-circuiting member Sc and the commutator mainbody are fixed to each other. Then, the cylindrical conductive platemember is cut into separate parts in the circumferential direction sothat the plurality of segments are formed. Further, the outercircumference terminal connection portions 91 are cut so that the outercircumference terminals 90 are spaced from one another in thecircumferential direction. As a result, an undercut process, in whichthe cylindrical conductive plate member is cut into separate parts inthe circumferential direction to form the segments, and a removingprocess, in which the outer circumference terminal connection portions91 are removed, are performed at the same time. In other words, thesegments are formed and the outer circumference terminal connectionportions 91 are removed in a single process. This reduces the number ofmanufacturing processes of the commutator and reduces the manufacturingcost of the commutator. Further, in this modification, hooking portionsmay be formed at the ends of the commutator main body opposite to itsends to which the short-circuiting member Sc is fixed. In this case, thecommutator main body may be used as a commutator that does not requirethe short-circuiting member Sc (that does not short-circuit).

In the commutator S of the above embodiment, twenty-four segments(segments 1 to 24) are short-circuited at an interval of 120 degrees.However, the number of segments and the angular interval at which thesegments are short-circuited may be changed.

For example, the commutator may include 16 segments that areshort-circuited at an interval of 180 degrees as shown in FIGS. 20 and21. More specifically, the short-circuiting member 96 includes twocomponents 96 a and 96 b that are arranged in the same plane and include16 outer circumference terminals 97 a and 97 b, sixteen innercircumference terminals 98 a and 98 b, and sixteen connection portions99 a and 99 b. Each of the connection portions 99 a and 99 b connectsone of the outer circumference terminals 97 a and 97 b and one of theinner circumference terminals 98 a and 98 b separated from one anotherby 90 degrees in the circumferential direction.

In this example, the connection portions 99 a and 99 b are curved in theaxial direction and thereby spaced from each other as shown in FIG. 21so that the connection portions 99 a and 99 b do not come in contactwith each other. FIGS. 20 and 21 do not show an insulator for fillingeach gap, and FIG. 21 schematically shows the cross-section of theconnection portions 99 a and 99 b to facilitate understanding. In thisexample, the outer circumference terminals 97 a and 97 b, the innercircumference terminals 98 a and 98 b, and the connection portions 99 aand 99 b all have the same thickness. In other words, the connectionportions 99 a and 99 b are curved and thereby spaced from each other inthis example so that each of the components 96 a and 96 b can be formedto have a uniform thickness (each of the components 96 a and 96 b doesnot need to be processed to have a partially different thickness). Thefirst and second components 96 a and 96 b may easily be obtained from aplate member having uniform thickness.

The connection portions 99 a and 99 b of the above modification may bemodified to connection portions 100 a and 100 b that are bent (folded)in the axial direction and are thereby spaced from each other so thatthe connection portions 100 a and 100 b do not come in contact with eachother as shown in FIG. 22.

In the above embodiment, the connection portions 35 a and 35 b arethinner than the outer circumference terminals 33 a and 33 b and theinner circumference terminals 34 a and 34 b (the stepped portions D areformed in the connection portions 35 a and 35 b). Alternatively, thethickness of the connection portions may be the same as the thickness ofthe outer circumference terminals 33 a and 33 b and the innercircumference terminals 34 a and 34 b (without the stepped portionsbeing formed), and an insulating paper may be interposed between theadjacent connection portions in the lamination direction.

In the above embodiment, the positioning recess 27 is formed in the mainbody insulator H, and the positioning projection 32 a is formed in theinsulator 32. However, the shape of the positioning recess 27 and theshape of the positioning projection 32 a may be changed as long as thepositioning recess 27 and the positioning projection 32 a enable thepositioning of the first and second components in the circumferentialdirection. Further, the positioning recess 27 and the positioningprojection 32 a may be eliminated.

In the above embodiment, the fitting recesses 37 a, 37 b, 38 a, and 38 band the fitting projections 39 a, 39 b, 40 a, and 40 b are formedalternately in the circumferential direction in the outer circumferenceterminals 33 a and 33 b and the inner circumference terminals 34 a and34 b. Alternatively, the fitting recesses and the fitting projectionsmay be formed only in the outer circumference terminals 33 a and 33 b oronly in the inner circumference terminals 34 a and 34 b. Further, thefitting recesses may be formed in all of the inner circumferenceterminals and the outer circumference terminals included in either oneof the first and second components, and the fitting projections may beformed in all the inner circumference terminals and the outercircumference terminals included in the other one of the first andsecond components. In this case, the shape of one of the two componentsslightly differs from the shape of the other one of the two components.However, the two components can be easily manufactured with themanufacturing apparatus used in the above embodiment (although the dieused in the first and second punching operation units 54 and 55 needs tobe changed partially). Further, the outer circumference terminals andthe inner circumference terminals may be fixed to each other throughwelding or the like to eliminate the need for the fitting recesses 37 a,37 b, 38 a, and 38 b and the fitting projections 39 a, 39 b, 40 a, and40 b.

In the above embodiment, each of the connection portions 35 a and 35 bis formed along an involute curve. However, each of the connectionportions 35 a and 35 b may be formed along another curve or may have asimple linear shape.

In the above embodiment, the recesses 25 are formed in the ends of thesegments 1 to 24, and the hooking portions 36 a and 36 b are fitted andfixed to the pair of arms 25 a that form the recess 25. Alternatively,the hooking portions 36 a and 36 b may be fixed to the segments 1 to 24(recess 25) through, for example, welding.

In the above embodiment, the punching process is performed by each ofthe first and second punching operation units 54 and 55 so that theconnection portions 35 a and 35 b are formed reversed from each other.Alternatively, the punching process may be performed by a singlepunching operation unit, and the lamination process may be performed ina manner that one of the two conductive plate members 53 is turnedaround to reverse the connection portions 35 a and 35 b with respect toeach other.

1. A short-circuiting member comprising: a plurality of components, eachhaving an outer circumference and an inner circumference, and each ofthe plurality of components including: a plurality of outercircumference terminals arranged along the outer circumference; aplurality of inner circumference terminals arranged along the innercircumference; and a plurality of connection portions, each connecting acorresponding one of the outer circumference terminals and acorresponding one of the inner circumference terminals with theconnection portions separated from each other by a predetermined anglein a circumferential direction, wherein: the plurality of outercircumference terminals, the plurality of inner circumference terminals,and the plurality of connection portions are substantially formed alongthe same plane; the plurality of components are laminated in a state inwhich the connection portions of one of the plurality of components arereversed to the connection portions of another one of the plurality ofcomponents; and the outer circumference terminals that are adjacent in alamination direction are in contact with each other, the surfaces of theinner circumference terminals that are adjacent in the laminationdirection are in contact with each other, and the connection portionsthat are adjacent in the lamination direction are not in contact witheach other.
 2. A short-circuiting member comprising: a plurality ofcomponents, each having an outer circumference and an innercircumference, and each of the plurality of components including: aplurality of outer circumference terminals arranged along the outercircumference; a plurality of inner circumference terminals arrangedalong the inner circumference; and a plurality of connection portions,each connecting a corresponding one of the outer circumference terminalsand a corresponding one of the inner circumference terminals with theconnection portions separated from each other by a predetermined anglein a circumferential direction, wherein: the plurality of outercircumference terminals, the plurality of inner circumference terminals,and the plurality of connection portions are substantially formed alongthe same plane; the plurality of components are laminated in a state inwhich the connection portions of one of the plurality of components arereversed to the connection portions of another one of the plurality ofcomponents; and the outer circumference terminals that are adjacent in alamination direction are in contact with each other, the innercircumference terminals that are adjacent in the lamination directionare in contact with each other, and the connection portions that areadjacent in the lamination direction are not in contact with each other,wherein: the adjacent connection portions are bent or curved in thelamination direction so as to be spaced from each other.
 3. Ashort-circuiting member comprising: a plurality of components, eachhaving an outer circumference and an inner circumference, and each ofthe plurality of components including: a plurality of outercircumference terminals arranged along the outer circumference; aplurality of inner circumference terminals arranged along the innercircumference; and a plurality of connection portions, each connecting acorresponding one of the outer circumference terminals and acorresponding one of the inner circumference terminals with theconnection portions separated from each other by a predetermined anglein a circumferential direction, wherein: the plurality of outercircumference terminals, the plurality of inner circumference terminals,and the plurality of connection portions are substantially formed alongthe same plane; the plurality of components are laminated in a state inwhich the connection portions of one of the plurality of components arereversed to the connection portions of another one of the plurality ofcomponents; and the outer circumference terminals that are adjacent in alamination direction are in contact with each other, the innercircumference terminals that are adjacent in the lamination directionare in contact with each other, and the connection portions that areadjacent in the lamination direction are not in contact with each other,wherein: each of the plurality of connection portions is thinner thanthe outer circumference terminals and the inner circumference terminalsin the lamination direction.
 4. The short-circuiting member according toclaim 3, further comprising: an interval maintaining member formaintaining an interval between the adjacent connection portions.
 5. Theshort-circuiting member according to claim 4, wherein: theshort-circuiting member further including an insulator arranged betweenthe adjacent connection portions; and the insulator includes apositioning portion for positioning the plurality of components in thecircumferential direction.
 6. The short-circuiting member according toclaim 1, wherein: each of the plurality of connection portions is formedalong an involute curve.
 7. A short-circuiting member comprising: aplurality of components, each having an outer circumference and an innercircumference, and each of the plurality of components including: aplurality of outer circumference terminals arranged along the outercircumference; a plurality of inner circumference terminals arrangedalong the inner circumference; and a plurality of connection portions,each connecting a corresponding one of the outer circumference terminalsand a corresponding one of the inner circumference terminals with theconnection portions separated from each other by a predetermined anglein a circumferential direction, wherein: the plurality of outercircumference terminals, the plurality of inner circumference terminals,and the plurality of connection portions are substantially formed alongthe same plane; the plurality of components are laminated in a state inwhich the connection portions of one of the plurality of components arereversed to the connection portions of another one of the plurality ofcomponents; and the outer circumference terminals that are adjacent in alamination direction are in contact with each other, the innercircumference terminals that are adjacent in the lamination directionare in contact with each other, and the connection portions that areadjacent in the lamination direction are not in contact with each other,wherein: at least either one of the plurality of outer circumferenceterminals and the plurality of inner circumference terminals includefitting recesses and fitting projections that are formed alternately inthe circumferential direction.
 8. The short-circuiting member accordingto claim 7, wherein: the fitting recesses and the fitting projectionsare formed in a substantially middle part of the plurality of outercircumference terminals or the plurality of inner circumferenceterminals.
 9. A commutator comprising: the short-circuiting memberaccording to claim 1; and a plurality of segments connected to theplurality of outer circumference terminals or the plurality of innercircumference terminals.
 10. A commutator comprising: a short-circuitingmember comprising: a plurality of components, each having an outercircumference and an inner circumference, and each of the plurality ofcomponents including: a plurality of outer circumference terminalsarranged alone the outer circumference; a plurality of innercircumference terminals arranged along the inner circumference; and aplurality of connection portions, each connecting a corresponding one ofthe outer circumference terminals and a corresponding one of the innercircumference terminals with the connection portions separated from eachother by a predetermined angle in a circumferential direction, wherein:the plurality of outer circumference terminals, the plurality of innercircumference terminals, and the plurality of connection portions aresubstantially formed along the same plane; the plurality of componentsare laminated in a state in which the connection portions of one of theplurality of components are reversed to the connection portions ofanother one of the plurality of components; and the outer circumferenceterminals that are adjacent in a lamination direction are in contactwith each other, the inner circumference terminals that are adjacent inthe lamination direction are in contact with each other, and theconnection portions that are adjacent in the lamination direction arenot in contact with each other; and a plurality of segments connected tothe plurality of outer circumference terminals or the plurality of innercircumference terminals, wherein: the plurality of segments form asubstantially cylindrical shape, and the commutator main body is formedat an inner side of the plurality of segments and has an accommodationportion for accommodating the short-circuiting member, wherein: theplurality of segments form a substantially cylindrical shape, and thecommutator main body is formed at an inner side of the plurality ofsegments and has an accommodation portion for accommodating theshort-circuiting member, and wherein: the plurality of segments eachhave a recess formed in an end of the segment; the plurality of outercircumference terminals each have a projection insertable in thecorresponding recess; and the short-circuiting member is arranged at anend of the commutator main body in a state in which the projections ofthe outer circumference terminals are inserted in the recesses of thesegments.
 11. A commutator comprising: a short-circuiting membercomprising: a plurality of components, each having an outercircumference and an inner circumference, and each of the plurality ofcomponents including: a plurality of outer circumference terminalsarranged along the outer circumference; a plurality of innercircumference terminals arranged along the inner circumference; and aplurality of connection portions, each connecting a corresponding one ofthe outer circumference terminals and a corresponding one of the innercircumference terminals with the connection portions separated from eachother by a predetermined angle in a circumferential direction, wherein:the plurality of outer circumference terminals, the plurality of innercircumference terminals, and the plurality of connection portions aresubstantially formed along the same plane; the plurality of componentsare laminated in a state in which the connection portions of one of theplurality of components are reversed to the connection portions ofanother one of the plurality of components; and the outer circumferenceterminals that are adjacent in a lamination direction are in contactwith each other, the inner circumference terminals that are adjacent inthe lamination direction are in contact with each other, and theconnection portions that are adjacent in the lamination direction arenot in contact with each other; and a plurality of segments connected tothe plurality of outer circumference terminals or the plurality of innercircumference terminals, wherein: the plurality of segments form asubstantially cylindrical shape, and the commutator main body is formedat an inner side of the plurality of segments and has an accommodationportion for accommodating the short-circuiting member, wherein: theplurality of segments form a substantially cylindrical shape, and thecommutator main body is formed at an inner side of the plurality ofsegments and has an accommodation portion for accommodating theshort-circuiting member, and wherein: the plurality of segments eachhave a recess formed in an end of the segment and include a pair ofarms; the plurality of outer circumference terminals includes a hookingportion, projecting through the corresponding recess, for hooking awinding wire; and each hooking portion is fixed by bending together thepair of arms of the corresponding recess.
 12. A commutator comprising: ashort-circuiting member comprising: a plurality of components, eachhaving an outer circumference and an inner circumference, and each ofthe plurality of components including: a plurality of outercircumference terminals arranged along the outer circumference; aplurality of inner circumference terminals arranged along the innercircumference; and a plurality of connection portions, each connecting acorresponding one of the outer circumference terminals and acorresponding one of the inner circumference terminals with theconnection portions separated from each other by a predetermined anglein a circumferential direction, wherein: the plurality of outercircumference terminals, the plurality of inner circumference terminals,and the plurality of connection portions are substantially formed alongthe same plane; the plurality of components are laminated in a state inwhich the connection portions of one of the plurality of components arereversed to the connection portions of another one of the plurality ofcomponents; and the outer circumference terminals that are adjacent in alamination direction are in contact with each other, the innercircumference terminals that are adjacent in the lamination directionare in contact with each other, and the connection portions that areadjacent in the lamination direction are not in contact with each other;and a plurality of segments connected to the plurality of outercircumference terminals or the plurality of inner circumferenceterminals, wherein: the plurality of segments form a substantiallycylindrical shape, and the commutator main body is formed at an innerside of the plurality of segments and has an accommodation portion foraccommodating the short-circuiting member, wherein: the plurality ofsegments form a substantially cylindrical shape, and the commutator mainbody is formed at an inner side of the plurality of segments and has anaccommodation portion for accommodating the short-circuiting member, andwherein: the plurality of outer circumference terminals each come incontact with an inner circumference of the corresponding segment.